JP-A-2000-100462 published by the Japanese Patent Office in 2000 discloses a technique wherein liquid fuel is sent to an evaporator according to the load of a fuel cell, and the liquid fuel is vaporized and supplied to a reformer. In the reformer, part or all of the hydrocarbon fuel is reformed into hydrogen according to the following equations (1) and (2).CnH2n+2+nH2O→nCO+(n+2)H2  (1)CO+H2O→CO2+H2  (2)
The hydrogen obtained by reforming is supplied to the anode of a fuel cell.